Well blocks are used in particular in continuous casting lines with vessels for the casting of metal melt, in particular as a fixed spout element with these types of Tundish. These Tundishs generally have a two-part casting channel which on the vessel side comprises a well block provided with a central through opening and on the die side a replaceable nozzle. The well block is embedded securely in the vessel bottom here, in particular is walled into the latter and is generally produced from a fire-proof ceramic material. The nozzle is produced from a heat-resistant fire-proof material and can easily be replaced. The separation point between the well block and the nozzle proves to be particularly critical here because at this separation point, if there is a leak, liquid steel can pass out and ambient air, in particular oxygen, is drawn into the melt flow and so has a negative impact on the quality of the metallic material. Therefore, this separation point should be as leakproof as possible, but is prone to serious cracking during the casting process.
It has therefore also already been proposed to prevent the increased formation of fissures and cracks in the region of the separation point with the aid of a specially configured nozzle. Such nozzles have a stop surface which can be subjected to contact forces in order to press the nozzle against the well block. Unfortunately, these devices prove to be mechanically complex and do not lead to the desired long-term stability.